Various different types of network services can be provided by network equipment deployed in networks of service providers. Network equipment can perform network services such as switching, routing, firewall protection, load balancing, and so forth. Traditionally, such network services have been performed by actual physical equipment, such as switches, routers, and so forth.
With improvements in processor technology, processors can be abstracted and partitioned to provide virtual network service modules that perform various network services, such as those listed above. By virtualizing hardware including processors, network services can be implemented as distinct software modules on top of a virtualization layer. This makes it possible to create virtual network topologies inside a particular hardware.
In some implementations, the virtual network service modules can be implemented within virtual entities referred to as “virtual racks,” which represent the virtualizations of physical network appliances or devices that are mounted and cabled within a network equipment rack in a data center, for example. The virtual network service modules of a virtual rack may be involved in a session in which packets are communicated in both a forward direction (forward flow) and a reverse direction (reverse flow). If the packets of such a session are not processed efficiently, such as processed by different service processors, then system inefficiency or even failure can occur.